The present invention relates to novel linear peptides with antimicrobial activity. Said peptides are made up of 11 amino acids, and they have the amino group of the amino acid constituting the N-terminal end in a non-derived form or functionalized with an acetyl group, p-toluene sulphonyl, benzyl or benzoyl. The amino acid constituting the C-terminal end of said peptides is in carboxamide form. The invention describes the synthesis and use of said peptides as antimicrobial agents to combat pathogenic bacteria for plants. The invention also relates to compositions containing said peptides and an auxiliary agent, and to a method for preventing and treating infections and diseases of plants caused by pathogenic bacteria.
